A choice between daily or on-demand pre-exposure prophylaxis (PrEP) regimens could be offered to men who have sex with men (MSM) with a lower risk of HIV, according to a study published in The Lancet.

The ANRS IPERGAY trial found that on-demand PrEP with oral tenofovir disoproxil fumarate (TDF) plus emtricitabine was associated with an 86% relative reduction of HIV-1 incidence compared with placebo among MSM at high risk of HIV. Researchers in this study aimed to investigate whether on-demand PrEP was similarly effective among individuals with lower exposure to HIV risk. 

The study included 400 participants randomly assigned to receive PrEP in a fixed-dose combination of 300 mg TDF and 200 mg emtricitabine per pill or placebo. The primary endpoint was the diagnosis of HIV-1 infection.

Participants were interviewed at each visit to assess the pattern of PrEP use. All participants enrolled in the modified intention-to-treat population of the double-blind phase of the ANRS IPERGAY trial were eligible for this post-hoc analysis.

Two-hundred seventy participants had at least 1 period of less frequent sexual intercourse with high PrEP adherence during the study, representing 134 person-years of follow-up and 31% of the total study follow-up. Six HIV-1 infections were diagnosed in the placebo group and none were diagnosed in the TDF plus emtricitabine arm, with a relative reduction of HIV incidence of 100%.

Based on the study findings, the study authors noted that a choice between daily or on-demand PrEP regimens could be offered to MSM who have less frequent sexual intercourse.

Antoni G, Tremblay C, Delaugerre C, et al. On-demand pre-exposure prophylaxis with tenofovir disoproxil fumarate plus emtricitabine among men who have sex with men with less frequent sexual intercourse: a post-hoc analysis of the ANRS IPERGAY trial. The Lancet. Published November 26, 2019. DOI: https://doi.org/10.1016/S2352-3018(19)30341-8. Accessed December 18, 2019.